The present invention relates to a coil unit utilized for non-contact power transmission using a coil, an electronic instrument, and the like.
In recent years, non-contact power transmission (contactless power transmission) that utilizes electromagnetic induction to enable power transmission without metal-to-metal contact has attracted attention. As application examples of non-contact power transmission, charging a portable telephone, charging a household appliance (e.g., telephone handset), and the like have been proposed.
JP-A-2006-60909 discloses related-art non-contact power transmission. In JP-A-2006-60909, a series resonant circuit is formed using a resonant capacitor connected to the output of a power transmission driver and a primary coil so that power is supplied from a power transmission device (primary side) to a power reception device (secondary side).
When performing non-contact power transmission, it is necessary to provide coil units in a primary-side instrument and a secondary-side instrument. In particular, when providing a coil unit in a small instrument, the coil unit is desired to have a reduced size. The coil unit is also desired to have a shape that allows easy handling as a component of the instrument. Moreover, it is necessary to prevent a situation in which a foreign object enters the coil unit and causes an electrical malfunction.
Several aspects of the invention may provide a coil unit that allows easy handling as a component and prevents entrance of a foreign object, and an electronic instrument using the coil unit.